What exactly is the deal with slide-out sidebar navigation? Is it a standard Holo thing? Is it not? 3rd-party developers aren't really sure what to do with it, and even Google-made apps are all over the place. Some apps have sidebar navigation, some don't. The ones that do have it all function a little differently and none of the implementations were actually any good - until now.
Google Earth and Google Shopper were just updated with a new sidebar design, and, well, have you seen them? Google has fixed the biggest problem I have with all the previous designs: unpredictability.
In order to understand what's so great about the new design, we have to talk about what's so crappy about the old designs.